Mount Athos (Greek: Όρος Άθως, Oros Athos; English pronunciation: /ˈæθ.ɒs/, Greek pronunciation: [ˈa.θɔs]) is a mountain and peninsula in Macedonia, Greece. A World Heritage Site, it is home to 20 Eastern Orthodox monasteries and forms a self-governed monastic state within the sovereignty of the Hellenic Republic. Spiritually, Mount Athos comes under the direct jurisdiction of the Ecumenical Patriarchate of Constantinople. Today Greeks commonly refer to Mount Athos as the "Holy Mountain" (Greek: Άγιον Όρος, Agion Oros/Hagion Oros). In Classical times, the peninsula was called Akté (Ακτή) (sometimes Acte or Akte).
The peninsula, the easternmost "leg" of the larger Halkidiki peninsula, protrudes 50 kilometres (31 mi)  into the Aegean Sea at a width of between 7 and 12 kilometres (4.3 and 7.5 mi) and covers an area of 335.637 square kilometres (129.59 sq mi). The actual Mount Athos has steep, densely forested slopes reaching up to 2,033 metres (6,670 ft). The surrounding seas, especially at the end of the peninsula, can be dangerous. In ancient Greek history two fleet disasters in the area are recorded: In 492 BC Darius, the king of Persia, lost 300 ships under general Mardonius (Herodotus "Histories" book VI (Erato), Aeschylus "The Persians"). In 411 BC the Spartans lost a fleet of 50 ships under admiral Epicleas. (Diodorus Siculus, "Bibliotheca historica" XIII 41, 1–3).
Though land-linked, Mount Athos is accessible only by a single boat, the St. Eshpigmenitis. The daily number of visitors entering Mount Athos is restricted and all are required to obtain a special entrance permit valid for a limited period. Only males are allowed entrance into Mount Athos, which is called "Garden of the Virgin" by monks, and Orthodox Christians take precedence in the permit issuance procedure. Only males over the age of 18 who are members of the Eastern Orthodox Church are allowed to live on Athos, either as monks or as workers.
SOURCE : WIKIPEDIA